如何在Angular中使用Karma-Jasmine对嵌套的if条件进行单元测试？

Question

我有一个函数，单元测试的覆盖率是75%，但是，我希望单元测试的覆盖率是100%。这是函数：

calculateRatingSummary(): void {
    if (this.averageRating > 0) {
        this.avgRatings = Math.trunc(this.averageRating);
        this.avgRatingCollection.length = this.avgRatings;
        this.noRatings = this.totalRating - this.avgRatings;
        if (this.averageRating % 1 > 0) {
            this.noRatings--;
        }
        this.noRatingsCollection.length = this.noRatings;
     } else {
        this.noRatingsCollection.length = this.totalRating;
    }
}

下面是我为这个方法编写的所有单元测试：

describe('calculateRatingSummary', () => {
        it('check if company has peer review average rating', () => {
            component.averageRating = 2.3;
            component.calculateRatingSummary();
            expect(component.avgRatingCollection).not.toBeFalse();
        });
        it('rating display with no decimals if it has or not', () => {
            component.averageRating = 3.6;
            component.calculateRatingSummary();
            expect(component.avgRatings).toEqual(3);
        });
        it('all rating stars displays as light shaded when averageRating is smaller than zero', () => {
            component.averageRating = 0;
            component.calculateRatingSummary();
            expect(component.noRatingsCollection.length).toEqual(5);
        });
        it('if averageRating has decimals, noRatings is noRatings minus 1', () => {
            component.averageRating = 4.1;
            component.calculateRatingSummary();
            expect(component.noRatings).toEqual(component.noRatings);
        });
    });

但是，如果在运行npm run test-cover && npm run cover-report时进行测试，则无法获得第一个嵌套

我得到了100%的通过测试，但75%的分支被覆盖，因为它说测试不包括：

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这种情况：

if (this.averageRating % 1 > 0) {
    this.noRatings--;
}

没有被测试覆盖，我想知道为什么？不管我怎么试，我都不能把它检测出来。你能帮帮我吗?

Answer 1

I think else condition is not met in any specs you are expecting, you can try this it might work as our motive is to satisy the else condition i.e.. this.averageRating % 1 < 0

Example spec -
it('if averageRating modulos 1 equal to less than 0', () => {
        component.averageRating = 2;
        component.calculateRatingSummary();
        expect(component).toBeTruthy();
});